This invention relates to an improved wrist and arm exerciser generally of the type employing hand grips and a resistance torque device therebetween that reacts to and resists relative turning motion applied through the hand grips. The invention is herein illustratively described by reference to the presently preferred embodiments thereof; however, it will be recognized that certain modifications and changes therein with respect to details may be made without departing from the essential features involved.
It has long been known, of course, that the development and strengthening of wrist and arm muscles can be accomplished through daily exercises that repeatedly stress the muscles and that uniformity of development requires working all the muscles. Among the better exercises of this nature are those which require the participant to pit the strength of one arm against the other. While "isometrics" excercises can be performed in variety sufficient to work most of the muscles, it is found that muscle strains that change due to motion or changes of position are very helpful. For example, wrist and arm exercises involving forceful turning of a rotary resistance torque device held between the hands about an axis parallel to the line of the shoulders and that may, if desired, be canted into different orientations relative to that line in order to vary the exercise are highly effective. Exerting turning force first in one direction and then oppositely in alternate sequence over a period of time, with the exercises graduated from easy beginnings to more strenuous effort as the strength and stamina of the participant develop are highly effective.
In the course of investigating prior art exercising devices, a number of United States patents were located of varying degrees of interest and pertinence as background to the present improvements. These are as follows: U.S. Pat. Nos. 3,955,655; 3,944,221; 3,807,729; 3,764,131; 3,717,338; 3,495,824; 3,396,967.
An important purpose of the present invention is to provide a rotary resistance torque type wrist and arm exerciser that, unlike those employing relatively rotatably elements worked against the increasing stress of a return spring, permits the user to incur or experience immediate selected resistance torque in response to and measured by turning effort applied in either direction through the hand grips. Another and related object is to provide such an exerciser that eliminates the disadvantages of working against friction discs or bands rubbing together. Wear, static friction to be overcome and a tendancy for resistance torque to decrease as relative rotation speed between the discs or bands is increased tend to impose certain torque charateristics on devices of this nature that are considered to be less than satisfactory.
An important object is to overcome such difficulties and limitations in a device of small bulk and weight requirements and economical to manufacture. More specifically, it is an object hereof to provide a device the units of which can be started into relative rotation smoothly without encountering a large starting resistance in either direction of rotation. A further object hereof is to devise a wrist and arm exerciser in which the resistance torque developed within it increases with attempts to increase the relative rotational speed of the units and which thereby inherently affords to the user a wide range of exercise forces available to the user without the necessity of making any mechanical adjustments. However, it is also an object hereof to devise such a mechanism or exerciser with provision for convenient adjustability of the relative rotation resistance torque characteritic thereof.
Still another object hereof is to provide a versatile exerciser in which the resistance torque device therein is readily adapted for interchangeability of hand grips of different types, including rounded knobs that enable the user to grip and hold the unit in different hand positions, thus to vary the exercises of the muscles in the wrist and forearms, and also a scissor-type hand grip arrangement in which the forces are borne in a different manner by the wrists and forearms without less taxing of the hand muscles.